Emulsion copolymerization of sulfur dioxide and unsaturated organic compounds with recovery of uncon-taminated unreacted sulfur dioxide



July 8, 1952 w. w. ROUCH 3 EMULSION COPOLYMERIZAT 0N 0F SULFUR DIOXIDEAND UNSATURATED ORGANIC COMPOUNDS WITH RECOVERY OF UNCONTAMINATEDUNREACTED SULFUR DIOXIDE 2 SHEETS-SHEET 1 Filed July 29, 1949 INVENTOR.W. W. CROUCH BY WM A 7' TORNEYS July 8, 1952 w. w. CROUCH 2,602,787

' EMULSION COPOLYMERIZATION QF SULFUR DIOXIDE AND UNSATURATED ORGANICCOMPOUNDS WITH RECOVERY OF UNCONTAMINATED UNREACTED SULFUR DIOXIDE FiledJuly 29, 1949 2 SHEETS-SHEET z A TTORNEYA Patented July 8, 1952 EMULSIONCOPOLYMERIZATION OF SULFUR DIOXIDE AND UNSATURATED ORGANIC COMPOUNDSWITH RECOVERY OF UNCON- TAMINATED UNREACTED SULFUR DI- OXIDE Willie W.Crouch, Bartlesville, Okla, assignor to Phillips Petroleum Company, acorporation of Delaware Application July 29, 1949, Serial No. 107,596

Claims. 1

This invention relates to the production of synthetic resinous materialsformed by reaction between sulfur dioxide and one or more unsaturatedorganic compounds. In one of its more specific aspects it relates to therecovery of uncontaminated unreacted sulfur dioxide from a system forreacting sulfur dioxide and unsaturated organic compounds for reuse inthat system.

It has been well known for a number of years that sulfur dioxide willreact with numerous unsaturated organic materials to formheteropolymeric resinous products. Apparently the resin is produced fromequimolar quantities of sulfur dioxide and the unsaturated organicmaterial. The reaction appears to take place only in the liquid phaseand it will proceed in the absence of catalysts only in the presence ofactinic light, or it will proceed in the presence of any one of a largenumber of catalytic materials, most of which appear to have oxidizingproperties, in the dark or in the light. Some of the more importantcatalysts for promoting this reaction are oxygen, hydrogen peroxide,ozone, various nitrates such as silver and lithium nitrates, nitrites,persulfates, chlorates, perchlorates, ascaridcle, ozonized olefins, etc.Organic compounds which ener into the formation of such resins includemono-olefins, cyclo-olefins, substituted aliphatic olefins such asstyrene, diolefins such as butadiene, isoprene, cyclohexadiene, and thelike, acetylenes and polyfunctional unsaturated compounds such as allylalcohol, vinyl acetate, allyl ethyl ether, o-allylanisole,o-allylphenol, p-bromoallylbenzene, methyl undecylenate, undecylenylalcohol, undecylenic acid, etc. When mixtures of such unsaturatedorganic compounds are used, the resulting resin appears to have beenformed by a copolymerization of the unsaturated compounds with sulfurdioxide since its properties do not correspond to blends of resinsproduced from the individual unsaturated organic compounds and oftenhave properties which are superior to any one of the resins producedfrom the individual unsaturated compounds. For many of the unsaturatedcompounds there appears to be a ceiling temperature above which thereaction does not take place, and in such instances it is necessary toconduct the resin-forming reaction at a temperature below the ceilingtemperature and, when forming the resin from a mixture or organicunsaturated compounds, it appears desirable to conduct the reaction at atemperature below the ceiling temperature of the material having thelowest ceiling temperature. The resin-forming reaction is somewhatexothermic and generally some provision must be made for removing theheat of reaction. All of these features are more fully described in theliterature.

The resins heretofore produced have generally been formed in thepresence of only a moderate excess of sulfur dioxide and have beenrecovered as solid materials possessing a horn-like appearance or havinga porous expanded form. These materials are tough and difficult tohandle. In order to secure successful commercial products it has beennecessary to grind these mechanically in order to form a finely dividedmaterial, thus facilitating removal of occluded impurities. Even whenground to a fine powder, it has often been diflicult to removecompletely all of the occluded impurities, such as uncombined reactantsand other materials either present in the reactants as charged to theprocess 01' introduced in processing and handling the resin. In someinstances it appears that the grinding procedure results in theintroduction of minute quantities of metallic impurities which affectthe clarity and general appearance of the molded products. Further, thegrinding procedure develops undesirable heat which tends to soften theresin and cause the ground particles of resin to fuse, thus increasingthe difliculty of the removal of impurities and in some instancesresulting in an unsatisfactory molding powder because of particle size.Also, even if the grinding.

operation results in a satisfactory,-fine powder, the removal ofoccluded impurities is difiicult and expensive.

A method, of which I am one of the inventors, has now been found and, asis disclosed in application Serial No. 8,755, filed February 16, 1948,by

Crouch and Gotten, whereby unsaturated or-.

ganic compounds and sulfur dioxide are caused to react to produceresinous products of varied properties andwide adaptability, saidproducts are readily freed from unreacted reactants and otherimpurities. The process comprises reacting the unsaturated compound andsulfur dioxide in aqueous emulsion in the presence of suitable catalystsand emulsifying agents. When the reaction is carried out in aqueousemulsion the materials remain in a fluid condition and can be agitatedreadily, thus maintaining adequate contact of the reactants at allstages of the conversion. Sulfur dioxide is maintained in the reactionsystem in an amount stoichiometrically in excess of the unsaturatedcompound. The unsaturated material employed in the polymerization withsulfur dioxide often contains small amounts of inert gaseoushydrocarbons, such as butanes, with which butene monomers are oftencontaminated. When employing conventional procedures for the recovery ofthe unreacted sulfur dioxide these inert hydrocarbons tend to remain inthe sulfur dioxide. Employment of the recovered sulfur dioxide in asubsequent reaction of sulfur dioxide and unsaturated organic materialresults in an undesirable accumulation of the inert hydrocarbons in thesystem.

An object of this invention is to react sulfur dioxide and anunsaturated organic compound to form a heteropolymeric resin. Anotherobject of the invention is to recover uncontaminated, unreacted sulfurdioxide from the reaction of sulfur dioxide and an unsaturated organiccompound for reuse in a subsequent reaction. Another object of theinvention is to effect production from sulfur dioxide and an olefinicmaterial of a resin in a finely divided form by means of'an improvedbatch-type operation. Another object of the invention is to effect acontinuous production from sulfur dioxide and an olefinic material of aresin in a finely divided form. Other and further objects and advantagesof this invention will be apparent to those skilled in the art uponstudy of the accompanying disclosure and discussion.

The production of materials of the polymeric type in aqueous emulsion iswell known. Emulsion polymerization methods are particularly importantand are widely used in the manufacture of synthetic rubber, and thelike. Usually, however; the monomers employed in these processes arecompounds such as butadiene, isoprene, chloroprene, methyl acrylate,methyl methacrylate, acrylonitrile, styrene, and the like. Thesemonomers are chemically neutral, that is, they have neither stronglyacidic nor basic properties. Furthermore, most of them have little or nosolubility in water so that when they are used in emulsionpolymerization processes they form a water-insoluble phase whichcontains substantlally all of the monomers. These compounds are alsonon-electrolytes, that is, any part of the material that enters thewater phase is not ionized and therefore does not interfere with theaction of the emulsifying agent.

In contrast to the above mentioned monomers, sulfur dioxide is highlysoluble in water and reacts with water to form an electrolyte, sulfurousacid, ,which has pronounced acidic properties. In the emulsioncopolymerization of sulfur dioxide with unsaturated compounds, thesulfur dioxide is divided between the aqueous and nonaqueous phases buta substantial portion of it remains in the aqueous phase which;as'hereinbefore mentioned, is quite acidic. The usual emulsifying agentsemployed for carrying out polymerization reactions are not applicable inthe presence of sulfur dioxide. In fact, the addition of an acidicelectrolyte such as sulfurous acid to a resin or rubber latex preparedin the usual way is known to be an effective means of coagulating thelatex and agglomerating the polymer. Thus it is entirely unobvious andunpredictable to one skilled in the art that emulsion polymerizationmethods can be applied to the production of copolymers in which sulfurdioxide is employed as a monomer.

It has now been found that satisfactory emulsion polymerization systemsmay be provided for the interaction of unsaturated organic compounds andsulfur dioxide through the use of selected emulsifying agents which areeffective at low pH. Thus, while emulsifiers such as fatty-acid soapsare inapplicable since they react with sulfurous acid, other emulsifierswhich are salts of strong acids may be used, for example, salts ofsulfonic acids. These latter compounds are more strongly acidic thansulfurous acid. Surface active salts of organic amines are alsoapplicable.

Figure 1 of the drawings is a schematic flow plan utilized in thepreferred modification of this invention. Figure 2 is a schematic flowplan of a modification of this invention.

Referring particularly to Figure 1 of the drawings, in a generalembodiment of the invention, a mono-olefin from chamber II, sulfurdioxide from chamber I2, water and an emulsification agent, which isactive in an acid medium, from chamber I3, and a catalyst, such aslithium nitrate, from chamber I4 are supplied to a first reactor chamberI5. The sulfur dioxide is readily dissolved in the water and an aqueoussolution of sulfur dioxide is formed within reactor I5. The materialsare mixed within reactor I5 by means of mixer I6 so as to form anemulsion of the mono-olefin with the aqueous sulfur dioxide solution asan oil-in-water type emulsion. Substantially equimolar quantities of themono-olefinic material and sulfur dioxide are reacted in reactor chamberI5 to form a heteropolymer. The heteropolymer-containing emulsion isremoved from the lower portion of reactor chamber I5 through conduit I7and valve I8 and is passed through heater I9 wherein the tempera ture ofthe heteropolymer-containing emulsion is raised to a temperature withinthe range of from F. to 185 F. Heater I9, as is diagrammatically shownin the drawings, is a coil-type heater and hot heat exchange material ispassed through the heater by means of conduits 2I and 22. Anyconventional heater may be utilized for the purpose of heating theemulsion material. Better operation is obtained if the emulsion materialis heated in heater I9 to a temperature within the range of between F.and F. The heated emulsion material is passed by way of conduit 20 intoa coagulator chamber 23. A coagulant is passed from chamber 24 by way ofconduit 25 and pump 26 into coagulator chamber 23. The coagulant and theheteropolymer-containing emulsion are intimately contacted by stirringwith mixer 21. The temperature of the material is maintained by passinga heat exchange medium through the lower portion of the coagulatorchamber by means of conduits 28 and 29.

Unreacted vaporized materials are removed from the emulsion material incoagulator chamber 23, preferably before the addition of the coagulant,and are removed therefrom through valve 3I and conduit 32, preferably atdiminished pressure (e. g., between 0.1 and 1 atmosphere), to compressor33. The gaseous materials are compressed in compressor 33 and are passedby means of a continuation of conduit 32 and valve 34 into the lowerportion of reactor chamber 35. Water and an emulsification agent fromchamber I3 and catalyst from chamber I 4 which have previously beensupplied to the reactor 35 through conduits 36 and 31 form a liquidfilter for the gaseous materials entering the lower portion of reactor35. Sulfur dioxide, being soluble in the water, is dissolved therein andother unreacted materials, such as other monomeric materials, saturatedhydrocarbons or air, which are insoluble in water at operatingconditions pass through the liquid in reactor 35 and are removed fromthe upper portion of reactor 35 through valve 38.

After removal of the unreacted materials from chamber 23, theheteropolymer, which is primarily in the form of a latex, is incondition for coagulation. The amount of the coagulant which is added tocoagulator 23 prior to the removal of the unreacted materials, if any,is ordinarily'quite small. After removal of the unreacted materials,sufficient coagulant is supplied to coagulator 23 to substantially breakdown the emulsion, coagulate the resin, and agglomerate the latextherein. The slurry of coagulum is then removed from the lower portionof coagulator 23 by means of conduit 39 for further processing.Mono-olefin from chamber II' and additional sulfur dioxide from chamberI2 is added to the aqueous solution in reactor 35 in such an amount thatthe sulfur dioxide therein is in an amount stoichiometrically in excessof the monoolefin. The mono-olefin is emulsified in the aqueous sulfurdioxide solution by stirring with stirrer 4!. The reaction between themonoolefin and the sulfur dioxide takes place within reactor 35 in themanner described in connection with reactor l5. After the coagulum hasbeen removed from coagulator 23 the emulsion is removed from the lowerportion of reactor 55 through conduit 62 and valve 43 and is passedthrough heater is as described hereinabove. Another batch reaction isthen started in reactor l5 in the same manner as described in connectionwith reactor In the modification shown as Figure 2 of the drawings,water and an emulsification agent from chamber [3, a polymerizationcatalyst from chamber is, sulfur dioxide from chamber [2, and amono-olefinic material from chamber llare continuously supplied toreactor 45 through conduits 35, 45, 4?, and 58. The sulfur dioxide isdissolved in the water and forms an aqueous solution for the purpose ofemulsifying the monoolefinic organic material. The materials are mixedwithin reactor t5 by means of stirrer 49 so as to form an emulsion ofthe mono-olefinic material in the aqueous solution of sulfur dioxide asan oil-in-water type emulsion. The amount of sulfur dioxide which ismaintained in reactor 45 is stoichiometrically in excess of themono-olefinic organic material. The mono-olefinic organic material andthe sulfur dioxide reacted in reactor 45 are removed with the emulsionfrom the lower portion thereof through conduit 5i and are passed throughheater 52 where the temperature of the emulsion is raised to atemperature within the range of between 140 F. and 185 F., preferablybetween 150 F. and 180 F. The emulsion is passed by a continuation ofconduit 5! through throttling valve 65 into flash chamber 53 in whichthe unreacted materials are flashed from the emulsion at the reducedpressure maintained in the fiash chamber and are removed from the upperportion of the flash chamber through conduit 54 through which they arepassed to compressor 55. Flash chamber 53 is maintained at diminishedpressure (e. g., between 0.1 and 1 atinto the lower portion of scrubbingtower 5t.v

Water is introduced into the upper portion of scrubbing tower 56 throughconduit 51 and passed downwardly through suitable packing in the towercountercurrent to the flow of the unreacted materials. Sulfur dioxide isdissolved by the water and water insoluble materials are removed fromthe upper portion of scrubbing tower 56 through conduit 58. The aqueoussolution of sulfurdioxide is removed from the lower portion of scrubbingtower 56 and is passed by means of conduit 59 into surge tank 6!. Theaqueous solution of sulfur dioxide is passed through conduit 62, throughpump 53 in conduit 48, and is supplied by means of conduit 48 as aportion of the aqueous sulfur dioxide for the reaction in reactor 45.The emulsion from which unreacted material has been removed is passedfrom the lower portion of flash chamber 53 by means of conduit 54 andpump into a coagulation chamber, not shown.

The processes described above have the im-.

portant advantages of enabling the sulfur dioxide to be recovered bydissolving in water instead of compressing and cooling the gas forstorage as liquid sulfur dioxide. Considerable saving is realized forthe reason that less compression of the liquid sulfur dioxide isrequired and less heat removal is needed. Still another advantage isthat though liquid sulfur dioxide which is obtained by the recovery ofsulfur dioxide and compression thereof in connection with apolymerization of unsaturated organic materials and sulfur dioxidemustbe fractionated to separate the aforementioned impurities, such asbutanes, from the sulfur dioxide, that purpose is economicallyaccomplished by the process of this invention. This is a commerciallysignificant point since for economic reasons it is desirable to employolefin monomers whichhave not been highly purified and therefore oftencontain constituents not reactive with sulfur dioxide.

Separation of the resin is effected by coagulation of the latex, such aswith brine-alcohol, brine-acid, solutions of electrolytes, etc.,followed by water washing, filtration, and drying of the product. Theresinous material thus obtained is a light, soft, fine white powder, itssolubility in various solvents depending upon the olefinic materialemployed. For example, when l-butene is used, the product is completelysoluble in acetone.

The process of this invention not only possesses numerous advantages forthe preparation of resins but it also yields stable latices asintermediate products. These latices are produced in the form ofemulsions and are extremely valuable for use in various impregnating andcoating operations, such as treatment of paper, cloth, and thelike, andthey may be mixed with other latices, such as a synthetic rubber latex,to produce a variety of materials. Since the latices are stable they canbe stored as such for indefinite periods. The resins, obtained bycoagulation of the latices, have many advantages over similar resinsprepared by methods heretofore employed. The resins are easily recoveredfrom the latices. They maybe made to precipitate in the form of afine-grained powder which can be filtered, dried, and Washed free ofemulsifier. They are useful as moldin powders and are applicable in anyof menu-,-

merous areas where resinous powderare employed.

Unsaturated organic compounds which are applicable in this invention arethose which will react with sulfur dioxide to produce heteropolymericcompounds, under the other conditions heretofore employed by the priorart. Most of such reactants contain an olefinic linkage, and may berepresented by the formula wherein R1 and R2 may be hydrogen, halogen,or alkyl, or R1 may be a constituent of a carbocyclic ring in which R4is a member, and R3 and R4 may be hydrogen, alkyl, alkenyl, aryl,aralkyl, or have an acetylenic linkage, or substituted groups thereofwherein substituentssuch as halo, nitro, hydroxyl, carbocyclic, cyano,and the like may be present, or R4. may be .a constituent of acarbocyclicring in which R1 is also a member. In general the olefiniccompound employed will not contain more than twenty carbon atoms permolecule. Examples of olefinic compounds which may beused include1-butene,.2-butene, propylene, isobutylene, pentenes, hexenes,.cyclohexene, butadienes, styrene, alphaemethyl styrene, alphachlorostyrene, vinyl acetylenes, vinyl chloride, vinyl bromide, and the like.It is also frequently desired to employ a mixtiu'e .of olefiniccompounds, rather than a single olefinic compound, in carrying out theprocess of this invention.

When operatingaccording to the-manner herein described, it is generallyfound that substantially equimolar proportions of olefinic compound andsulfur dioxide react together. In order to facilitatethe reactionbetween the monorolefinic organic material and sulfur dioxide in anaqueous solution, however, an amount of sulfur dioxide which isstoichiometrically in excess of the unsaturated organic material isused. It is sometimes desired to use a molar excess of sulfur dioxide onthe order of 2:1 molratio of sulfur dioxide to olefinic material. Inother cases it is even more desirable to use a. higher ratio, forexample, a ratio of 5:1 or greater, depending upon operating conditions,olefinic material employed, the amount of aqueous medium, etc, althoughit appears that even in such cases equimolar quantitles of sulfurdioxide and olefinic compound enter into reaction. Frequently it will bedesirable to remove the reactants from the reaction zone,.and separateunreacted materials, when between about '70 and about 97 per cent of thereactant present in the lesser amount has reacted. When some diolefinsare used as reactants, under some conditions, these materials tend toundergo homopolymerization to form rubber-like products; such reactionsare undesired in my invention and conditions should be chosen with suchdioleflnic reactants, to inhibit such homopolymerization and favor jointinterreaction to pro-' duce heteropolymeric resins.

Emulsifying agents which are applicable are those which are active in anaqueous medium which has a pH below 7. The aqueous medium in theemulsion used generally has a pH of about '1 to 2, and sometimes has apH as low as about 0.5. The emulsifying agent used should, of course, beeffective at the pH of the aqueous medium in the reaction mixture. Amongthe compounds which have been found effective are the long chaina'lkylsodium sulfates and the branched chain aliphatic or aromaticsodium sulfonates, salts of organic bases suchas amine salts, andquaternary ammonium salts. Examples .of these materials are laurylsodium sulfate, diamyl sodium sulfosuccinate, di-secondary-butylnaphthalene sodium sulfonate, dodecylamine hydrochloride, dodecylaminesulfate, and the like. The amount of emulsifying agent employed is thatquantity which is necessary to produce a stable emulsion of theingredients. In some cases an amount as low as about ,1 part per partsreactants (olefin'plus sulfur dioxide) is considered sufficient andusually an amount not to exceed about 10 parts is added.

Catalysts applicable inthis-process are the same as those which havebeen found effective when carrying out the reaction between olefiniccompounds and sulfur dioxide by methods heretofore employed. Examples ofthese catalytic materials include nitrates of the alkali metals andammonium, nitric acid, potassium persulfate, hydrogen peroxide, organicperoxides, such as cumene hydroperoxide, peracetic acid, and the like.The amount of catalyst used may vary over a wide range and will dependupon th material chosen. In cases where alkali metal nitrates orammonium nitrate are employed, the amount may vary from 0.03 to 0.60part per 100 parts reactants with an amount ranging from 0.15 to 0.45part being generally preferred. With other materials the quantity ofcatalyst used may be somewhat higher but in any event it is determinedby the case at hand.

Temperatures for carrying out the resin-producing reactions of thisinvention usually fall within the ran e of from 10 F. to 140 F., andpreferably from within the range of 50 F. to F. In some instances,however, it may be deemed advisable to employ temperatures below 10 F.in order to get a more satisfactory reaction.

Obviously when polymerizations are carried out in aqueous emulsion inthe absence of freezing point depressants, temperatures below thefreezing point of the acidic aqueous medium cannot be employed. The useof various additive'agents, however, makes a process of the typedisclosed herein applicable at lower temperatures. An example of such alow temperature system is a glycerin-water solution. and the termaqueous emulsion should be construed to include the use of an aqueousmedium comprising water and a sufficient amount of a water-solublecomponent to lower thefreezing point below the desired polymerizationtemperature, whether or not the, actual polymerization temperature isalcovev or below freezing. It is generally preferred that the emulsionbe of an oil-in-water type, with the ratio of aqueous medium to organicmonomeric material between about 1.5:1 and about 10:1, in parts byweight. At low ratios the emulsions tend to have high viscosities and athigh ratios the yield per unit volume of reactor per unit of time islow. In the practice of the invention, suitable means will be necessaryto establish and. maintain an emulsion and to remove reaction heat tomaintain a desired reaction temperature. The polymerization may beconducted in batches, semicontinuously, or continuously as discussedabove. Th total pressure on the reactants is preferably at least asgreat asv the total vapor pressure of the mixture, so that the initialreactants will be present in liquid phase.

Advantages of this invention are illustrated by the following example.The reactants and their proportions and other specific ingredients ofthe recipe are presented as being typical and should not be construed tolimit the invention unduly.

Example An emulsion polymerization was effected according to thefollowingrecipe:

Prepared from (C -C14) alkyl benzenes.

The polymerization was effected with agitation for four hours at 77 F.Analysis of a sample of th latex formed showed that it contained 41.8parts of the original 88.3 parts of sulfur dioxide charged to thereactor. A second reactor was charged with the same quantities of water,sodium alkyl benzene sulfonate and lithium nitrate given in theaboverecipe. The latex was heated to 180 F. and excess sulfur dioxide wasvented from the latex to the second reactor and finally was pumped witha compressor from the first reactor to the second reactor. Thefirstreactor, after cooling, had an absolute pressure of about 200millimeters of mercury at 75 F. The second reactor which contained therecovered sulfur dioxide absorbed in the water therein was analyzed forsulfur dioxide. The analysis showed that 38.7 parts or 92.3 weight percent of the unreacted sulfur dioxide was recovered in the secondreactor.

To the contents of the second reactor were added 46.7 parts l-butene andenough additional sulfur dioxide to make a total sulfur dioxide contentof 88.3 parts. A second reaction was then effected in the same manner asthe first. Polymerization proceeded at the same, high rate as in thefirst reaction to yield a similar latex of l-butene-sulfur dioxideresin;

These data disclose the fact that a very high rate of recovery ofuncontaminated, unreacted sulfur dioxide is obtained by the process ofthis invention; The recovery of the unreacted sulfur dioxide in thismanner eliminates the requirement for relatively expensive liqueficationand fractionation steps which have heretofore been necessary.

As will be evident to those skilled in the art various modifications ofthis invention can be made or followed in the light of the foregoingdisclosure and discussion without departing from the spirit or scope ofthe disclosure. Several operating variations will b immediately apparentto those skilled in the art. For instance, in a batch operation thelatex need not be removed from the reactor chamber before removal of theexcess sulfur dioxide therefrom. It is, however, advantageous to utilizethe method which is disclosed for the reason that heating of thelatexcontaining emulsion facilitates the removal of the gaseousmaterial. It is also within the scope of this invention to dissolve thesulfur dioxide in water before passing it into the reactor chamber. Inyet another modification of the invention, it is sometimes desirableduring the last phase of stripping the latex under vacuum to introducelive steam or an inert gas into the latex to facilitate removal of theremaining small portion of sulfur dioxide.

1 claim:

1. The process of claim 7, wherein additional sulfur dioxide is added tosaid water from a separate source so as to concentrate sulfur dioxidetherein in an amount in molar excess of mono-olefinic organic materialwith which it is emulsified. a v

2. The process of claim 7, wherein said unreacted'materials are removedfrom the reaction mixture by heating the emulsion to a temperaturewithin, the range of from F. to F. and maintaining said emulsion at apressure of 0.1 and 1 atmosphere. v

3; The process of claim 7, wherein said water is maintained in a reactorzone; removing'water insoluble material from said reactor zone; pass inga polymerization catalyst and an emulsifying agent which is active in anacid medium into said reactor zone; adding a mono-olefinic organiccompound to said reactor zonein an amount stoichiometrically less thanthat required to react all of said sulfur dioxide dissolved in saidwater; and emulsifying said mono-olefinic organic material insaidaqueous. sulfur dioxide solution as an oil-in-water type emulsion.Q. In the process of claim 7, the improvement of passing waterdownwardly through a scrubbing zone; passing unreacted materials intothe lower portion of said scrubbing zone and upwardly therethrough incontactwith said downflowing water, whereby sulfur dioxide is dissolvedin said water and is-separated from water insoluble materials; removingundissolved material from said scrubbing zone; passing the resultingaqueous solution of sulfur dioxide to gether with a polymerizationcatalyst and an emulsifying agent which is activ in an acid medium intoa reaction zone; passing additional sulfur 1 dioxide and saidmono-olefinic organic material into said reaction zone in amounts suchthat sulfur dioxidetherein is in molar excess of said mono-olefinicorganic material. 7 5. The process of. claim/l, wherein said emulsion isheated to a temperature within therange of from 140 *Frto 185 151.; andsaid unreacted materials are removed from said emulsion at a pressurebetween 0.1 andl atmospherep 6. An improved process for preparing aresin and latex comprising charging water, a first portion of anemulsifying agent which is active in an acid medium, a polymerizationcatalyst, a mono-olefinic organic material, and sulfur dioxide in anamount stoichiometrically in excess of said mono-olefinic organicmaterial, to a first reaction zone; dissolving said sulfur dioxide insaid water; emulsifying said mono-olefinic organic material in saidaqueous solution of sulfur dioxide to form an oil-in-water emulsion;reacting at least equimolar quantities of said monoolefinic organicmaterial and said sulfur dioxide to form a heteropolymer; passing saidheteropolymer containing emulsion from said first reaction zone througha heat exchange zone wherein said heteropolymer containing emulsion isheated to a temperature between 140 F. and 185 F.; passing saidheteropolymer containing emulsion into a coagulation zone whereinunreacted materials are removed from said emulsion at a pressure of from0.1 to 1 atmosphere; passing said unreacted materials into a body ofwater in a second reaction zone, wherein unreacted sulfur dioxide isdissolved in said water and Water insoluble materials are separatedtherefrom; removing said water insoluble gaseous materials from saidsecond reaction zone; passing a coagulant into said coagulation zone anddispersing said coagulant in said emulsion; whereby the structure ofsaid emulsion is broken down; recovering resulting resin from saidcoagulation zone; passing a second portion of said emulsifying'agent, apolymerization catalyst, avmonooleiinic organic material, and additionalsulfur dioxide to said second reaction zone, the amount of said sulfurdioxide therein being at. least equimolarwith said mono-oleflnic organicmaterial; and repeating the steps of reaction and recovery recited inconnection with the materials charged to said first reaction zone.

1; An improved process for preparing aresin which comprises emulsifyingamono-olefinic orgsni'c material in an aqueous solution of sulfurdioxide, said. sulfur dioxide being in an amount inexcess of amoi ratioof 1:1 with said monooIefln; effecting a reaction between said sulfurdioxide and said mono-oleflnic organic compound 'toproduce aheteropolymeric reaction product; removing unreacted materials from saidemulsion, recovering a resulting resin from said emulsion and passingsaid unreacted materials into water, whereby unreacted sulfur dioxide isdissolved in said water-and -is separated from water insolublematerials; emulsifying said resulting sulfur dioxide solution withadditional mono-oleflnic organic material in such an amount that saidsulfur dioxide is at least equimolar with said mono-olefinic organicmaterial; and reactingsaidsulfur dioxide with said additionalmonooleiinicorganic material.

8. Animproved process for recovery of purifled unreacted sulfur dioxidefrom a process for theproduction of'heteropolymers by reacting astoichiometrically excessive amount of sulfur dioxide with amono-olefinic organic material reactable with sulfur dioxide in anaqueous emulsion, which comprises the stepsof'separating unreactedmaterials from said heteropolymers; and passing said unreacted materialsthrougha water bath, whereby said sulfur dioxide is dissolved-in saidwater and is-separated from any water insoluble unreacted material.

9'. An improved process for recovery of purified unreactedsulfur dioxidefrom a process for-the productionof heteropolymers by reacting in anaqueousrnedium a stoichiometrically excessive amount of sulfur dioxidewith an unsaturated organic material in which the unsaturation isbetween two adjacent carbon atoms and which will interact with sufurdioxide to form a resin, which comprises the steps of separatingunreacted materials from said heteropolymers; and passing said unreactedmaterials through a water bath whereby sulfur dioxide is. dissolved insaid-water and is separated from any water insoluble unreacted.material.

10. An improved process for preparing, a resin which comprisesemulsifying an unsaturated organic material .in which the unsaturationislietween two adjacent'carbon atoms and which will interact with sulfurdioxide to form. a resin in an. aqueous solution of sulfur dioxide,.said sulfur dioxide being. in an amount in excess of 8. .mol ratio. of1:1. withsaid unsaturated. organic. material; effecting :a reactionbetween said sulfm' dioxide and said unsaturated organic material toproduce a heteropolymeric reaction product; removingumeacted materialsfrom said emulsion. recovering a resulting resin from said emulsion andpassing said unreacted materials into water,

- whereby unreacted sulfur dioxide is dissolved in said water and isseparated from water insoluble materials; emulsify said resultingsulfurdioxide solution with additional said unsaturated organic materialin such an. amount that said sulfur dioxide is at least equimolar with.said unsaturated organic material and reacting said sulfur dioxide withsaid additional unsaturated organic material.

WILLIE W'. ,CRQUCH.

REFERENCES CITED The foliowingreferences are .ofirecord in thefileofthis patent:

UNITED STATES'PATEN'IS.

Number Name Date 2,371,719 Starkweather Mar. 20, 1945 2,453,039Schribner et' al. Nov. 2, 1948 2,462,013 Waterman Feb. 15, 1949

7. AN IMPROVED PROCESS FOR PREPARING A RESIN WHICH COMPRISES EMULSIFYINGA MONO-OLEFINIC ORGANIC MATERIAL IN AN AQUEOUS SOLUTION OF SULFERDIOXIDE, SAID SULFUR DIOXIDE BEING IN AN AMOUNT IN EXCESS OF A MOL RATIOOF 1:1 WITH SAID MONO-OLEFIN; EFFECTING A REACTION BETWEEN SAID SULFURDIOXIDE AND SAID MONO-OLEFINIC ORGANIC COMPOUND TO PRODUCE AHETEROPOLYMERIC REACTION PRODUCT; REMOVING UNREACTED MATERIALS FROM SAIDEMULSION, RECOVERING A RESULTING RESIN FROM SAID EMULSION AND PASSINGSAID UNREACTED MATERIALS INTO WATER, WHEREBY UNREACTED SULFUR DIOXIDE ISDISSOLVED IN SAID WATER AND IS SEPARATED FROM WATER INSOLUBLE MATERIALS;EMULSIFYING SAID RESULTING SULFUR DIOXIDE SOLUTION WITH ADDITIONALMONO-OLEFINIC ORGANIC MATERIAL IN SUCH AN AMOUNT THAT SAID SULFURDIOXIDE IS AT LEAST EQUIMOLAR WITH SAID MONO-OLEFINIC ORGANIC MATERIAL;AND REACTING SAID SULFUR DIOXIDE WITH SAID ADDITIONAL MONOOLEFINICORGANIC MATERIAL.